Drug firm Gilead is restricting remdesivir to countries with bigger outbreaks of coronavirus, but if it becomes available it will be included in the Australian trial, the researchers say.
It was revealed on Tuesday that testing could also be expanded to include the head lice treatment drug ivermectin, after Monash University researchers suggested it could kill the virus in a test tube within 48 hours.
The study, dubbed ASCOT, will operate across 70 hospitals in Australia and 11 in New Zealand, with the Royal Melbourne Hospital already recruiting patients.
It will examine the effects of HIV drug lopinavir-ritonavir and hydroxychloroquine, which is commonly used to treat malaria, lupus and rheumatoid arthritis. Research will observe the body's natural immune system to determine whether it can prevent COVID-19 patients from becoming so ill they require intensive care.
Previous clinical trials using these two drugs to treat COVID-19 patients have produced mixed results.
A recent study of 199 Chinese COVID-19 patients, published by the prestigious New England Journal of Medicine, found lopinavir-ritonavir did not lead to greater clinical improvements than standard supportive care, nor did it decrease viral load or improve the chance of survival in coronavirus patients.
Controversy also surrounds the use of hydroxychloroquine, with some of the more than 80 global medical trials so far showing promising results while others suggest the anti-viral treatment is not effective in treating the deadly virus.
"The aim is really to see whether using these drugs will prevent patients deteriorating to the point of needing a ventilator," said lead researcher Associate Professor Steven Tong, an infectious disease clinician at the Royal Melbourne Hospital.
"Some studies have shown that these two drugs can work against the virus in the laboratory, but we need to now test them in patients to know for sure whether they will work in humans.
"Drugs that show promise in the laboratory don’t always translate into being effective in patients."
Renowned infectious diseases expert Professor Sharon Lewin, who is also leading the research, said both of the drugs had been shown to have "direct activity against the virus". "We know that from studies in test tube models, that while they're not super-potent drugs, they definitely have activity," she said.
Fellow researcher Professor David Paterson, from the Royal Brisbane and Women's Hospital, said the benefit of using lopinavir-ritonavir and hydroxychloroquine was that the antiviral treatments had been used for years, so the side effects were known and all patients would be monitored closely.
As part of the trial, a portion of patients will be given lopinavir-ritonavir only, while another study group will be treated with hydroxychloroquine.
The two drugs will also be trialled in combination to see if they work better together and some patients will not be treated with either drug, so researchers can compare their immune responses to participants who are given the anti-viral treatments.
Researchers also hope the 18-month trial will help alleviate the severity of virus symptoms in the absence of a vaccine.
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Melissa Cunningham is The Age's health reporter.
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